Answer
$$\tan\theta$$
Work Step by Step
Simplify
$$\sin^{2}\theta\csc\theta\sec\theta.$$
Use the Reciprocal Identities
$$\csc\theta=\frac{1}{\sin\theta}$$
and
$$\sec\theta=\frac{1}{\cos\theta}$$
to obtain
$$\sin^{2}\theta\csc\theta\sec\theta=\sin^{2}\theta\bigg(\frac{1}{\sin\theta}\bigg)\bigg(\frac{1}{\cos\theta}\bigg)=\frac{\sin\theta}{\cos\theta}=\tan\theta,$$
with the last equality based on the Tangent Identity.